Adding LED downlights to lighting circuit

[BenW86]

First post after months of stalking these forums!

In my attic I have four 20W MR16 halogen lights in the ceiling. Powered from a 240->12V transformer (max output 105W). These lights are driven from a supply taken from the ceiling rose in the bedroom below.

I've bought 2 sets of LED downlights for lighting under the eaves. They take a live and a neutral connection. I'd like to turn on/off or even control from a dimmer independent of the current room switch as I'd want one set on and the other off at different times. My question is can I cut into the main 240V supply, before the split off to switch/transformer for the current lights, insert a junction box and add the LED lights in.

Pictures are below:
Black is the current wiring and green is what I'd like to add
http://imgur.com/WionisN

I would wire the junction box like this:
http://imgur.com/hnN39mk

Does this seem sensible/safe as a way to add the lights? The room is currently getting redone so walls are exposed, I can properly chase cables etc.

Any help would be appreciated,

Cheers

 

[deadshort]

All good, if the led's are external as is the driver with 240v outside i would use a DP switch.

Regards,

DS

 

[PrenticeBoyofDerry]

You will need dimable LEDs, I assume these are to be 240V rather than 12V?
Also any junction boxes/Joint boxes must be left in an accessible location for inspection, testing and maintenance or a maintenance free method of jointing the cables must be used.